High-voltage variable resistor unit

Abstract

A high-voltage variable resistor unit capable of permitting a circuit board to be decreased in size and preventing interruption of output thereof. A circuit board having a resistive pattern including a plurality of variable resistance elements formed on a front surface thereof is arranged in a board receiving chamber. A terminal fitment and a slide element are so arranged that a contact point between a plate-like section of the slide element and a contact section of the terminal fitment is defined in a manner to be spaced from the front surface of the circuit board toward an operation member. A fit projection of the terminal fitment is fitted in a fit hole of the insulating casing. A silicone adhesive is applied to a board supporting rib of the insulating casing to the circuit board thereto. The adhesive is constructed so as to exhibit sufficient to prevent elastic force of the arm from being reduced to a degree of causing a failure in contact between the contact section and the supported section of the slide element when it is cured.

What is claimed is: 
     
       1. A high-voltage variable resistor unit comprising: a circuit board formed on a front surface thereof with a resistive pattern including at least one variable resistance element of an arcuate shape;   an insulating casing made of an insulating resin material said casing defining a board receiving chamber in which said circuit board is received and including a board supporting rib to which said circuit board is joined by means of an adhesive;   an operation member including an operation shaft rotatably inserted through said insulating casing;   at least one slide element arranged between said circuit board and a portion of said operation member positioned in said insulating casing, said at least one slide element including a supported section supported on said operation member;   said slide element being slid on said at least one variable resistance element when said operation member is operated; and   at least one terminal fitment including a contact section contacted with said supported section of said slide element so as to permit pivotal movement of said slide element, a terminal section and a contact support section for connecting said contact section and terminal section to each other and electrically connected to said slide element;   said terminal fitment and slide element being arranged such that said slide element is contacted with said contact section of said terminal fitment at a contact point, said contact point being spaced from said front surface of said circuit board toward said operation member, said terminal section of said terminal fitment being positioned outside said at least one variable resistance element;   said contact support section of said terminal fitment including an arm provided on a distal end thereof with said contact section and exhibiting elastic force for forcing said contact section against said supported section of said slide element and an intermediate portion positioned between said terminal section and said arm and interposed between said board supporting rib and said circuit board;   wherein said adhesive for joining said circuit board to said board supporting rib being constructed so as to exhibit elasticity sufficient to permit said elastic force of said arm to ensure electrical contact between said contact section and said supported section after said adhesive is cured.   
     
     
       2. A high-voltage variable resistor unit as defined in claim 1, wherein said adhesive is a silicone adhesive. 
     
     
       3. A high-voltage variable resistor unit as defined in claim 2, wherein said adhesive exhibits Shore hardness of D10 to D40 and elongation of 150 to 250% after it is cured. 
     
     
       4. A high-voltage variable resistor unit comprising: a circuit board formed on a front surface thereof with a resistive pattern including a variable resistance element of an arcuate shape;   an insulating casing made of an insulating resin material said casing defining a board receiving chamber in which said circuit board is received and including a board supporting rib to which said circuit board is joined by means of an adhesive;   an operation member including an operation shaft rotatably inserted through said insulating casing;   a slide element arranged between said circuit board an a portion of said operation member positioned in said insulating casing and including a supported section supported on said operation member;   said slide element being slid on said variable resistance element when said operation member is operated; and   a terminal fitment including a contact section contacted with said supported section of said slide element so as to permit pivotal movement of said slide element, a terminal section and a contact support section for connecting said contact section and terminal section to each other and electrically connected to said slide element;   said terminal fitment and slide element being arranged such that said slide element is contacted with said contact section of said terminal fitment at a contact point, said contact point being spaced from said front surface of said circuit board toward said operation member, said terminal section of said terminal fitment being positioned outside said arcuate variable resistance element;   said contact support section of said terminal fitment including a fit projection fitted in a fit hole formed in said board supporting rib, an extension arranged so as to extend along a side surface of said insulating casing defining said board receiving chamber, a connection for connecting said fit projection and extension to each other, and an arm provided on a distal end thereof with said contact section and exhibiting elastic force for forcing said contact section against said supported section of said slide element;   wherein said adhesive for joining said circuit board to said board supporting rib being constructed so as to exhibit elasticity sufficient to prevent said elastic force of said arm from being substantially reduced when it flows along said extension of said terminal fitment to at least a position between a part of said extension and said side surface of said insulating casing and then cured.   
     
     
       5. A high-voltage variable resistor unit as defined in claim 4, wherein said fit projection of said terminal fitment is integrally provided with a biting means which bites into a surface defining said fit hole to keep said fit projection from being removed from said fit hole. 
     
     
       6. A high-voltage variable resistor unit as defined in claim 4, wherein said fit projection is formed into a shape like a flat plate; and said biting means is constituted by a pair of projections arranged on a pair of edges of said fit projection defined in a width direction thereof in a manner to be projected therefrom outwardly in said width direction;   said projections in a pair each including a tapered portion increased in width as it recedes from a distal end of said fit projection fitted in said fit hole and a biting angular portion arranged rearwardly of said tapered portion based on said distal end.   
     
     
       7. A high-voltage variable resistor unit as defined in claim 4, wherein said terminal fitment is so arranged that said terminal section of said terminal fitment is positioned outside said arcuate variable resistance element in a radial direction thereof and said arm of said contact support section upwardly traverses said variable resistance element while being spaced from said variable resistance element. 
     
     
       8. A high-voltage variable resistor unit as defined in claim 4, wherein said extension of said terminal fitment is formed with a raised portion; said raised portion having a fixed end positioned on a side of said arm and being raised on a side of said fit projection;   said raised portion having a free end formed into a shape which permits it to bite into said side surface of said insulating casing defining said board receiving chamber when said terminal fitment is moved in a direction away from said insulating casing.   
     
     
       9. A high-voltage variable resistor unit as defined in claim 4, wherein said insulating casing is integrally formed on a surface thereof opposite to said front surface of said circuit board with a pair of projections in a manner to extend toward said front surface of said circuit board; and said arm of said contact support section of said terminal fitment is fitted at a distal portion thereof between said projections.   
     
     
       10. A high-voltage variable resistor unit comprising: a circuit board formed on a front surface thereof with a resistive pattern including a plurality of variable resistance elements of an arcuate shape;   an insulating casing defining a board receiving chamber in which said circuit board is received and including a board supporting rib to which said circuit board is joined;   an operation member including an operation shaft rotatably inserted through said insulating casing;   a plurality of slide elements each arranged between said circuit board and a portion of said operation member positioned in said insulating casing and including a supported section supported on said operation member;   said slide elements being slid on said variable resistance elements when said operation member is operated; and   a plurality of terminal fitments each including a contact section contacted with said supported section of said slide element so as to permit pivotal movement of each of said slide elements, a terminal section and a contact support section for connecting said contact section and terminal section to each other;   said terminal fitments being electrically connected to said slide elements corresponding thereto, respectively;   each of said terminal fitments and each of said slide elements being so arranged that said supported section of said slide element is contacted with said contact section of said terminal fitment at a contact point spaced from said front surface of said circuit board toward said operation member;   said contact support section of each of said terminal fitments including a fit projection fitted in a fit hole formed in said board supporting rib, an extension arranged so as to extend along a side surface of said insulating casing defining said board receiving chamber, a connection for connecting said fit projection and extension to each other, and an arm constructed so as to exhibit elastic force for forcing said contact section against said supported section of said slide element;   said board supporting rib being formed with a groove in which said connection of said contact support section is fitted so as not to interfere with joining of said circuit board thereto;   said circuit board being joined to said board supporting rib and said connection fitted on said groove by means of an adhesive;   said adhesive being constructed so as to exhibit elasticity sufficient to prevent said elastic force of said arm from being reduced to a degree of causing a failure in contact between said contact section and said supported section of said slide element when it is cured to join a part of said extension of said terminal fitment or both said extension and a proximal portion of said arm to said side surface of said insulating casing defining said board receiving chamber.   
     
     
       11. A high-voltage variable resistor unit as defined in claim 10, wherein said adhesive exhibits Shore hardness of D10 to D40 and elongation of 150 to 250% after it is cured. 
     
     
       12. A high-voltage electrical component comprising: a circuit board formed on a front surface thereof with a circuit pattern;   an insulating casing defining a board receiving chamber in which said circuit board is received and including a board supporting rib to which said circuit board is joined by means of an adhesive;   a conductive member arranged in said board receiving chamber and electrically connected to said circuit pattern; and   a terminal fitment electrically connected to said conductive member;   said terminal fitment including a contact section contracted with said conductive member, a terminal section and a contact support section for connecting said contact section and terminal section to each other;   said contact support section of said terminal fitment including an arm provided on a distal end thereof with said contact section and exhibiting elastic force for forcing said contact section against said conductive member and an intermediate portion positioned between said terminal section and said arm and interposed between said circuit board and said board supporting rib;   wherein said adhesive for joining said circuit board to said board supporting rib being constructed so as to exhibit elasticity sufficient to permit said elastic force of said arm to ensure electrical contact between said contact section and said conductive member after it is cured.   
     
     
       13. A high-voltage electrical component as defined in claim 12, wherein said adhesive exhibits Shore hardness of D10 to D40 and elongation of 150 to 250% after it is cured. 
     
     
       14. A high-voltage electrical component comprising: a circuit board formed on a front surface thereof with a circuit pattern;   an insulating casing made of an insulating resin material and defining a board receiving chamber in which said circuit board is received and including a board supporting rib to which said circuit board is joined by means of an adhesive;   a conductive member arranged in said board receiving chamber and electrically connected to said circuit pattern; and   a terminal fitment electrically connected to said conductive member;   said terminal fitment including a contact section contacted with said conductive member, a terminal section and a contact support section for connecting said contact section and terminal section to each other;   said contact support section of said terminal fitment including a fit projection fitted in a fit hole formed in said board supporting rib, an extension arranged so as to extend along a surface of said insulating casing defining said board receiving chamber, a connection for connecting said fit projection and extension to each other, and an arm provided at a distal end thereof with said contact section and constructed so as to exhibit elastic force for forcing said contact section against said conductive member;   said board supporting rib being formed with a groove in which said connection of said contact support section is fitted so as not to interfere with joining of said circuit board thereto;   wherein said adhesive being constructed so as to exhibit elasticity sufficient to prevent said elastic force of said arm from being reduced to a degree of causing a failure in contact between said contact section and said conductive member when it is cured to join said extension of said terminal fitment or both said extension and a proximal portion of said arm to said surface of said insulating casing defining said board receiving chamber.